THE BOAT FLY.-This insect, called Notonecta glauca, is thus described by Barbut. "It has a head somewhat round, of which the eyes seem to take up the greatest part. These eyes are brown, and very large, the rest of the head being yellow. In the fore-part it has a sharp trunk, that projects, and is inflected between the fore feet. On the sides are seen the antennæ, very small, yellowish, and which spring from under the head. The thorax, which is broad, short, and smooth, is yellow on the fore, and black on the back part. The escutcheon is large, of a rough black, and as it were nappy. The elytra, rather large, and crossed over each other, are a mixture of brown and yellow, not unlike the colour of rust, which makes it look cloudy. The under part of the body is brown; and at the extremity of the abdomen are to be seen a few hairs. The feet, six in number, are of a light brown, the two hindermost having on the leg and tarsus hairs that give them the shape of fins, nor are they terminated by nails. The four anterior ones are somewhat flat, and serve the animal to swim with; but at their extremity they have nails, and no hairs. This insect is seen in stagnating waters, where it swims on its back, and presents its abdomen upwards; for which reason it has been called by the Greek name of notonecta. The hinder feet, longer than the rest, serve it as paddles. It is very nimble, and dives down when you go to take hold of it; after which, it rises again to the surface of the water. It must be cautiously handled, if one would avoid being pricked by it, for the point of its rostrum is exceedingly sharp, and intolerably painful, but it goes off in a few minutes. The larva very much resembles the perfect nsect." Such is the account that Mr. Barbut gives of this beautiful nimble little creature. To this account, however, we shall add the following:-Its legs are long; when taken cut of the water, it hops; it is very common in the ponds of water in Hyde Park, and in several other places about London. It is of a very particular form, being flattish at the belly, and rising to a ridge on the middle of the back; so that when it swims, which is almost always on the back, its body has much the resemblance of a boat in figure,-whence its vulgar name. It is eight lines long, three broad, and two and a half thick. The belly is jointed, striated, and, as Barbut observes, hairy. Nature has provided it with an offensive weapon resembling a sting, which it thrusts out when hurt,. from a large opening at the tail. The head is large and hard; the eyes nearly of a triangular form. The nose is a long, green, hollow proboscis, ending in a hard and sharp point, which in its natural posture remains under the belly, and reaches to the middle pair of legs. The outer part of its wings are of a pale flesh-colour, with spots of a dead white; these are long, narrow, and somewhat transparent; they terminate in a roundish point, and perfectly cover the whole body. The triangular piece which stands between the top of the wings is hard, and perfectly black; the inner wings are broader and shorter than the outer ones; they are thin and perfectly transparent, and are of a pale pearl-colour. The hinder pair being greatly longer than all the rest, they serve as oars; and nature has tufted them with hair at the end for that purpose. This creature mostly lives in the water, where it preys on small insects, killing them, and sucking their juices with its proboscis, in the manner of the water scorpion and many other aquatic insects: it seizes its prey violently, and darts with incredible swiftness to a considerable distance after it. Though it generally lives in the water, it sometimes, however, crawls out in good weather; and drying its wings by expanding them in the sun, takes flight, and becomes an inhabitant of the air, not to be known as the same creature, unless to those who had accurately observed it before : when tired of flying, or in danger of an enemy, it immediately plunges into the water. We are told that there are fourteen species of it, seven of which are common in Europe, in wa ters, &c. EPHEMERAL FLIES.-This species of insect is named ephemeral, because of its very short existence in the fly state. It is one of the most beautiful species of flies, and undergoes five changes. At first, the egg contains its vital principle; it comes forth a small caterpillar, which is transformed into a chrysalis, then into a nympha, and lastly, into a fly, which deposits its eggs upon the surface of water, where the sun's rays bring them to life. Each egg produces a little red worm, which moves in a serpentine manner. They are found in abundance during the summer, in ponds and marshes; and as soon as cold weather sets in, the little worm makes for itself a shell or lodging, where it passes the winter; at the end of which it ceases to be a worm, and enters into its third state, that of a chrysalis. It then sleeps till spring, and gradually becomes a beautiful nympha, or a sort of mummy, something in the form of a fish. At the time of its metamorphosis, the nympha at first seems inactive and lifeless; in six days, the head appears, raising itself gradually above the surface of the water; the body next disengages itself slowly and by degrees, till at length the whole animal comes out of its shell. The newborn fly remains for some minutes motionless upon the water, then gradually revives, and feebly shakes its wings, then moves them quicker, and attempts first to walk, then to fly. As these insects are all hatched nearly at the same time, they are seen in swarms for a few hours flitting and playing upon the surface of the water; they then lay their eggs, and soon after die. Thus they terminate their short life in the space of a few hours, and the same day that saw them born, witnesses their death THE BUTTERFLY. Behold, ye pilgrims of this earth, behold! Thomson The first thing which fixes our attention on beholding these aerial inhabitants, is, the clothing with which they are adorned. Yet some of them have nothing in this respect to engage our notice, their vestment is simple and uniform; others have a few ornaments on the wings; but with some, those ornaments amount to profusion, and they are covered with them all over. This last species will occupy us for a short interval. How beautiful are the gradations of colour which decorate them! what harmony in those spots which relieve the other parts of their attire! with what delicacy has nature pencilled them! But, whatever may be my admiration when I consider this insect by the naked eye, how greatly is it augmented, when I behold this beautiful object through the medium of the microscope! Would any one ever have imagined, that the wings of butterflies were furnished with feathers? Nothing, however, is more true; and what we commonly call dust, is found in reality to be feathers. Their structure and arrangement are adjusted to as perfect symmetry, as their colours are soft and brilliant. The parts which form the centre of these little feathers, and which immediately touch the wing, are the strongest; those, on the contrary, which compose the exterior circumference, are much more delicate, and of an extraordinary fineness. All these feathers have a quill at their base, but the superior part is more transparent than the quill from which it proceeds. If we lay hold of the wing too rudely, we destroy the most delicate part of the feathers; but if we remove all that we term dust, there remains only a thin transparent skin, where may be distinguished the little orifices in which the quill of each feather was lodged. This skin, from the nature of its texture, may be as easily discerned from the rest of the wing, as a fine gauze from the cloth on which it is |